With the playoffs looming and his defense lacking, Red Bulls coach Bruce Arena finally shook up his lineup.

His changes paid off with a 2-1 win over Kansas City last night, a victory that was their first sound defensive effort in weeks and clinched a first-round MLS Cup date with New England.

Juan Pablo Angel scored twice off gaffes by defender Jose Burciaga Jr. to snap a five-game winless streak for the Red Bulls (12-11-6, 42 points). They will try to snap an eight-game winless skid against the Revolution, playing a home-and-home Oct. 27 at Giants Stadium and Nov. 3 at Gillette Stadium.

Burciaga’s handball in the box set up Angel’s 20th-minute penalty kick. After Jack Jewsbury tied the match 30 seconds later, when Burciaga fell down and lost the ball to Dane Richards, the winger fed Angel for a 24th-minute goal that proved the game-winner in front of 20,083.

“[Yesterday] was about building for the playoffs, getting the team in good shape and getting confidence,” Angel said. “We were more clever, we kept possession, and we were clinical when he had the opportunity to finish off the game.”